New construction pre-wired for solar and powerwall

[BrandonSinger]

Can anyone give me recommendations of what is needed to prewire for solar (roof or panels) and power wall 2.

I have seen some awful solar installations with bright silver conduit running down the exterior side of the house.

I would like to go ahead and run this conduit during the construction phase just in case. Any specifics would be much appreciated.

 

[Racerx22b]

I'm not a solar installer or electrician but based on my installation experience I'd have them run conduit (it will need to be metal) to an empty electrical box nearby where you will want your inverter installed. That should terminate in the attic or wherever your solar panel wires will come from). If you know what inverter you are going to use find out where the DC wires go into. I have a Solar Edge inverter and the DC feed goes into the bottom right side of the inverter. If this is what you will use have the box installed at the height you estimate the bottom of the inverter to be at and then just to the right of where you want the inverter to be installed.

I would also have the builder run as many extra unused conduit pipes as possible from your electrical panel to your attic (or wherever all your wiring goes to from the panel before being spread out across the house). Most builders run at least one but I'd have them do as many as possible. This might not be useful for the solar but it is a great way to future proof your house.

Just so you can map it out in your head..

The panels will all be wired together then all that wiring will go to a box (likely installed on your roof under the panels). The DC current will then come from the panels down to your inverter to be converted to AC power. Depending on your local code, those wires will likely need to be in metal conduit. That power will then leave your inverter as AC power and will go to your main electrical panel. For my install, this wire did not have to be in metal conduit. I would map all the install locations now and then discuss your needs with your builder so the proper conduit can be installed before drywall goes in. Ideally, your inverter will be installed next to your main electrical panel mounted or on the exterior of your house opposite your main panel (personal preference). Keeping the wire runs as short as possible alleviates potential install issues or unnecessary current loss.

Here is a pic of mine. Sorry for the blurriness. I had to zoom in from a non related pic.

 

[Shygar]

I'm getting my Powerwall 2 installed in a couple weeks. I ran a cat6 ethernet cable there as I was told it can use wifi and ethernet.

 

[BrokerDon]

Also try to provide for your solar / Powerwall 2 to provide power when the grid goes down... At least to critical circuits:

• refrigerator
• router / Ethernet switch
• egress lighting
• garage door openers
• selected outlets to charge your portable electronics
• kegerator / wine cooler LOL

 

[Shygar]

Garage door opener, I didn't think about that, makes sense.

 

[SoundDaTrumpet]

I would recommend the following:
1. Route plumbing vents to allow a large rectangular areas to be free from obstructions. This will make the panels sit pretty on the roof. I consider carbon monoxide/heat carrying vents from water heater, furnace, and dryer to be non-negotiable. Plan for a western exposure for PV, and put the vents on the north face or out of the way.
2. Install conduit inside the wall for the DC conduit (for string inverters) (or paint the conduit to match if this deluxe option is over the top). (Unpainted conduit is not permitted in my city). Route it from somewhere in the attic and bring it in the vicinity of your power meter.
3. Route empty conduit for low voltage wires (for Ethernet to communicate with inverter). NEC prohibits mixing low voltage with power. I liked mine protected.
4. Put two ethernet drops nearby where the solar inverter or power wall go. I have one luckily for the inverter and plan to takeover the once used telephone line (Cat 5) for powerwall too.
5. Reserve plenty of wall space on the exterior for the inverter and powerwalls. I have a minimally sized garage and didn't even like the solar subpanel that installed. I can open all doors of both cars when parked and hope to keep it that way. A concrete footing* would be useful for ground mount, and the only way to stack powerwalls. [(*)Tesla has a line item if you choose this option, price was reasonable.]

As a disclaimer: Item (1) above I didn't think about until too late. Item (2) seemed too intrusive and didn't want to add cost. (3) was easily accommodated.(4) was blessed to have home-run pre-installed. (5) was fortunately put in with my landscaping work.

Most of the above can be dealt with at the time of solar/PV installation, so I would aim for getting at least two extra Ethernet runs from your closest to the telephone box. My installer did offer the option to run Ethernet zip tied to DC conduit up to my attic to the network closet. I did not want exposed Cat 5 (non-pro look and bad network security).

Beyond this there are solar ready main panels, and perhaps recommend a separate meter instead of a combination meter load center. Ideally the gateway is between the meter and load center. It be interesting how they plan to the electrical work on my installation (whether or not 120% back feed rating is applicable with a smart Tesla Gateway... also panel is a main lug only so wonder how that works since it's all supply side as nothing is protecting the service wire other than a load calculation... not an electrician here...)

 

[oktane]

Have the roofer install the racks ahead of time so penetrations are done to their standards. In fact, I'd say smartest thing is to plan the solar along with your construction, coordinating with roofer, electrician, and PV contractor. Silly to "prewire" etc. since ROI will be 6 years. No sense in living in the house and burning a year or two.

 

[Racerx22b]

You'll find many solar contractors that have no interest in having their work looked at by inspectors during construction. Post construction inspectors seem to be super lazy in my neck of the woods. He didn't even open up anything to inspect connections or even go on the roof. Just eyeballed it from the road. And of course there were mistakes later discovered by FPL when they installed net meter.

 

[miimura]

When I had my house built I had all the roof penetrations away from the planned solar area. I also had the solar installer put the junction boxes and racking standoffs on the roof before the roof was shingled. My solar uses Enphase micro-inverters and the AC solar circuits were installed while the walls were open. No conduit needed inside or out.